'ITICA SLATE AND HUDSON-EIVER GROUP. 253 



308. 4. CALYMENE ( Species undetermined ). 

 Pl. LXVr. Fig3. 3a,b. 



Caudal shield with seven or more articulations in the lateral lobes, and fen in the 

 middle lobe ; articulations of the lateral lobes of the thorax and caudal shield with a 

 distinct groove extending nearly their entire length ; extremities obtuse ; lateral lobes 

 nearly once and a half the width of the middle lobe. 



The width of the lateral lobes of the thorax, compared with the middle lobe, is much 

 greater than in Calymene heckii, and somewhat greater than in C. senaria. The continuous, 

 nearly direct, groove in the articulations of the lateral lobe, is different from the same in 

 C. senaria, and may perhaps prove a sufficient distinction to identify fragments of the two 

 species. The two fragments figured are the only parts of the fossil yet observed, and from 

 these the crust is entirely removed, so that no aid in distinguishing the species can be 

 obtained from the surface markings. 



Fig. 3 a. A part of the thorax, preserving eight or nine articulations. 

 Fig. 3 b. The caudal shield, with a few segments of the thorax. 



Position and locality. These specimens were obtained in the Utica slate, near Canajo- 

 harie, Mohawk valley. The Calymene heckii occurs in the same locality. 



{From Mr. Everett, Principal of the Canajoharie Academy.) 



309. 5. ASAPHUS1 LATIMARGINATA {n.sp.). 



Pi.. LXVI. Figs. 4 a, b. 

 Compare Ataphut tyrannus, Mvschison, Sil. System, 1839, pag. 662, pi. 25, fig. 1 o 6. 



Caudal shield with fourteen articulations in the lateral lobes, and about the same 

 number in the middle one ; the posterior articulations of the latter lobe join the axis in an 

 acute angle, and all terminate in a flat border ; surface ( of exfoliated portions ) marked 

 by imbricating lamellose striae ; outer surface of the crust finely punctured. 



The fragment of a caudal shield of a much larger specimen ( fig. 3 6), was found in 

 the same stone as the other, and, from its surface markings, doubtless belongs to the same 

 species. The articulations are narrow, as in Asaphus tyrannus, and terminate in a broad 

 flat border ; it is impossible, however, to decide that it is identical with that species. It also 

 bears some analogy with the fragment found in the Birdseye limestone, but on comparison 

 proves clearly distinct. 



